Field of the Invention
The invention relates to a fingerprint sensor, and more particularly to a fingerprint sensor that is protected from electrostatic discharge (ESD).
Description of the Related Art
In recent years, biological identification technology has become increasingly mature, and different biological features can be used for identifying users. Since the recognition rate and accuracy of fingerprint identification technology are better than those of other biological feature identification technologies, fingerprint identification and verification are used extensively in various areas.
Fingerprint identification and verification technology detects a user's fingerprint pattern, captures fingerprint data from the fingerprint pattern, and saves the fingerprint data as a template. Thereafter, the user presses or slides a finger on or over the fingerprint sensor so that a fingerprint is captured and compared with the template. If the two match, then the user's identity is confirmed.
With the continued miniaturization of the integrated circuits (ICs) used in fingerprint sensors, these integrated circuits have become more susceptible to damage caused by electrostatic discharge (ESD). ESD is a phenomenon that occurs when excess charges are transmitted from the I/O pins to the integrated circuit too quickly, damaging the internal circuit.
Therefore, it is desired to dispose ESD protection circuits into a fingerprint sensor to protect the devices and circuitry of the integrated circuit against ESD damage.